Experimentally induced liver metastases from colorectal cancer can be prevented by mononuclear phagocyte-mediated monoclonal antibody therapy.

BACKGROUND & AIMS: Development of liver metastases is a frequent complication in patients with colorectal cancer (CRC), even after successful resection of the primary tumor. As such, post-operative adjuvant therapies that aim to eliminate residual disease after surgery may improve patient outcome. METHODS: We used a colon carcinoma liver metastases model, in which CC531s colon carcinoma cells are injected into the portal circulation by a surgical procedure. As injected tumor cells are arrested in the liver, this model is suitable for investigating the interaction of tumor cells with the liver microenvironment. By administering tumor specific monoclonal antibodies (mAb) directly post-operatively, we were able to determine the effect of antibody therapy on eradication of arrested tumor cells and subsequent liver metastases outgrowth. RESULTS: We showed that post-operative treatment with tumor specific monoclonal antibodies (mAb) prevents liver metastases outgrowth. Antibody-dependent phagocytosis (ADPh) was the main mechanism involved, as enhanced uptake of tumor cells by innate mononuclear phagocytes in the liver was observed after mAb therapy. Furthermore, Kupffer cells (KC) were identified as the most prominent effector cells, as depletion of KC abolished therapeutic efficacy. This was partly compensated by monocytes when animals were treated with a high mAb dose, but monocytes were unable to phagocytose tumor cells when rats were treated with low mAb doses. CONCLUSIONS: The finding that KC and monocytes can eliminate tumor cells through ADPh has important and promising clinical implications for designing new adjuvant therapies for patients undergoing CRC resection.

Experimental antibody therapy of liver metastases reveals functional redundancy between Fc gammaRI and Fc gammaRIV.

Many patients with colorectal cancer will develop liver metastases, even after successful surgical removal of the primary tumor at a time at which no visible metastases are present. We previously demonstrated that surgery--although mandatory--paradoxically enhances the risk of developing liver metastases. Because Ab therapy has been acknowledged as a successful strategy to treat malignancies, we studied the potential of postoperative adjuvant Ab therapy to prevent outgrowth of liver metastases. Treatment with murine anti-gp75 (TA99) mAb completely prevented outgrowth of B16F10 liver metastases in over 90% of mice. Therapeutic efficacy was maintained in either C1q- or complement receptor 3-deficient mice but was completely abrogated in FcR gamma-chain knockout mice. This indicates that the classical complement pathway was not essential, but interaction with activatory Fc gammaR was necessary for successful therapy. TA99-treatment was still effective in Fc gammaRI(-/-), Fc gammaRIII(-/-), Fc gammaRI/III(-/-), and Fc gammaRI/II/III(-/-) mice, suggesting an important role for Fc gammaRIV. However, wild-type mice that were treated with TA99 Abs and an Fc gammaRIV blocking Ab (mAb 9E9) were protected against development of liver metastases as well. Only when both Fc gammaRI and Fc gammaRIV functions were simultaneously inhibited, TA99-mediated curative Ab treatment was abrogated, indicating functional redundancy between both IgG receptors in the liver. Furthermore, depletion of liver macrophages (Kupffer cells) reduced the efficacy of Ab therapy, supporting that Kupffer cells are involved as effector cells. Importantly, since Ab treatment almost completely prevented development of liver metastases, postoperative adjuvant Ab therapy may help to improve patient prognosis.

Prevention of secondary displacement and reoperation of distal metaphyseal forearm fractures in children.

BACKGROUND: Metaphyseal distal forearm fractures are common in paediatric patients and treating these fractures by reduction and cast immobilization alone is under debate, since secondary displacement is a frequent complication that often warrants re-intervention. This study was conducted to invest the incidence of secondary displacement and re-intervention for non-displaced and displaced fractures, with or without fixation. MATERIAL AND METHODS: A retrospective cohort study was conducted analysing all consecutive paediatric patients under the age of 16 with distal metaphyseal forearm fractures throughout a 2-year period. Data were recorded on radiographic characteristics, OTC/AO-classification, type of treatment, reduction technique, surgical interventions and removal of hardware and complications. RESULTS: 200 Patients with displaced metaphyseal forearm fractures were included of which 139 were primarily treated in the emergency room, the other 61 patients were primarily treated in the operating room. 83% Of the patients had a satisfactory reduction in the emergency room and 94% of these patients were treated successfully with casting alone. A total of 84 patients were treated in the operating room of whom 30% underwent reduction and K-wire fixation, and 70% underwent reduction and casting only. 47% Of the patients treated with closed reduction without K-wire fixation in the operating room suffered from secondary displacement, of which 80% needed re-intervention. CONCLUSION: Metaphyseal forearm fractures can be treated with a very high success rate by closed reduction and casting alone in the emergency room. Reduction and casting of displaced metaphyseal forearm fractures in children that needed treatment in the operating room however, resulted in unacceptable high rate of secondary displacement and commonly required re-intervention. Those patients should therefore be treated by reduction and K-wire fixation.

The perioperative period is an underutilized window of therapeutic opportunity in patients with colorectal cancer.

OBJECTIVE: In this review, we address the underlying mechanisms by which surgery augments metastases outgrowth and how these insights can be used to develop perioperative therapeutic strategies for prevention of tumor recurrence. SUMMARY BACKGROUND DATA: Surgical removal of the primary tumor provides the best chance of long-term disease-free survival for patients with colorectal cancer (CRC). Unfortunately, a significant part of CRC patients will develop metastases, even after successful resection of the primary tumor. Paradoxically, it is now becoming clear that surgery itself contributes to development of both local recurrences and distant metastases. METHODS: Data for this review were identified by searches of PubMed and references from relevant articles using the search terms "surgery," "CRC," and "metastases." RESULTS: Surgical trauma and concomitant wound-healing processes induce local and systemic changes, including impairment of tissue integrity and production of inflammatory mediators and angiogenic factors. This can lead to immune suppression and enhanced growth or adhesion of tumor cells, all of which increase the chance of exfoliated tumor cells developing into secondary malignancies. CONCLUSIONS: Because surgery remains the appropriate and necessary means of treatment for most CRC patients, new adjuvant therapeutic strategies that prevent tumor recurrence after surgery need to be explored since the perioperative therapeutic window of opportunity offers promising means of improving patient outcome but is unfortunately underutilized.

Blocking alpha2 integrins on rat CC531s colon carcinoma cells prevents operation-induced augmentation of liver metastases outgrowth.

UNLABELLED: Currently, an operation is the only curative option for patients with colorectal cancer. Unfortunately, many patients will develop liver metastases even after successful resection of the primary tumor. Removal of primary colorectal carcinoma may paradoxically increase the risk of metastases development, because accumulating evidence suggests that surgical trauma can stimulate tumor growth. In the present study, we investigated the effects of abdominal trauma on liver metastases development. Surgical trauma dramatically increased adhesion of tumor cells in the liver, leading to enhanced outgrowth of metastases. Endothelial stress was observed rapidly after an operation, suggesting that abdominal trauma resulted in impairment of blood vessel integrity. Tumor cells preferentially adhered to extracellular matrix (ECM). Furthermore, preincubation of tumor cells with anti-alpha2 integrin antibodies completely reverted operation-induced augmentation of CC531s adhesion and liver metastases outgrowth. As such, we postulate that blood vessel integrity in the liver is compromised after abdominal trauma, resulting in enhanced ECM exposure, which enables tumor cell adhesion and metastases outgrowth. CONCLUSION: Perioperative treatments that either aim to reduce endothelial stress or block the interaction between tumor cells and ECM represent promising new therapeutic strategies for the prevention of liver metastases development after resection of the primary tumor.

Preoperative granulocyte/macrophage colony-stimulating factor (GM-CSF) increases hepatic dendritic cell numbers and clustering with lymphocytes in colorectal cancer patients.

Despite surgery with curative intent, approximately 30% of colorectal carcinoma patients will develop liver metastases during follow-up. Synchronous occult micrometastases, tumor cell shedding into the portal circulation and postoperative immune impairment have all been suggested to facilitate outgrowth of liver metastases. In experimental models, increases in both number of resident macrophages of the liver, the so-called Kupffer cells (KC), and tumoricidal capacity of KC were observed after pretreatment with granulocyte/macrophage colony-stimulating factor (GM-CSF), a potent immuno-stimulatory agent. Following perioperative recombinant human GM-CSF (rhGM-CSF), we previously showed activation of the systemic immune response in the postoperative period, which is normally transiently down-modulated after surgery. Therefore, in this pilot study, effects of preoperative rhGM-CSF administration on the composition of human liver immune cell population were evaluated in patients undergoing surgery for colorectal cancer. No difference in KC numbers of rhGM-CSF-treated patients was observed. Importantly, however, a 6-fold increase in dendritic cell (DC) numbers was observed compared to control patients, as quantified by immunohistochemistry of liver biopsies, taken during laparotomy. Furthermore, direct contact between liver CD8+ cells and DC was significantly enhanced in rhGM-CSF-treated patients. Both increases in DC numbers and DC interaction with CD8+ T cells suggest enhanced immunological activation, which may reduce liver metastases formation and ultimately improve survival after initial colorectal surgery.

Advanced colorectal cancer resulting in acute bowel obstruction during pregnancy; a case report.

INTRODUCTION: Abdominal pain is frequently found in the pregnant population; however life-threatening pathology such as colorectal cancer does occur rarely. As such, intestinal obstructions are usually attributed to pregnancy-related issues. We present the case of a young woman with an acute bowel obstruction caused by advanced colorectal carcinoma. PRESENTATION OF CASE: A 34-year old pregnant woman was referred to our emergency department with complaints of severe upper abdominal pain. Initial investigations did not show abdominal pathology and conservative treatment for obstipation was commenced. However, complaints persisted and a near blowout of the colon was diagnosed, prompting a caesarean section and diagnostic laparotomy. An obstructing tumour was found and a left-sided hemi-colectomy was performed. Unfortunately, skeletal, lymphatic and additional hepatogenic metastasis were discovered during chemotherapy and treatment was discontinued. DISCUSSION AND CONCLUSION: The mainstay of abdominal complaints during pregnancy can be attributed to normal physiological alterations associated with gravidity. Nonetheless serious pathology should be considered, especially when conservative treatment fails. On this note, diagnostic imaging during pregnancy should be used promptly upon suspicion of serious abdominal pathology.

Therapeutic potential of Kupffer cells in prevention of liver metastases outgrowth.

Development of liver metastases is a frequent complication in the course of gastro-intestinal malignancies. After entering the liver via the portal circulation, blood-borne tumor cells that have been seeded from primary colorectal cancer, are first encountered by Kupffer cells (KC), which line the liver sinusoids. KC represent approximately 10% of all liver cells, and have the ability to kill tumor cells. As such, they may play an important intrinsic role in the protection against outgrowth of hepatic metastases. Furthermore, the cytotoxic function of KC is increased upon stimulation with various biological response modifiers, such as interferon-gamma, granulocyte macrophage-colony stimulating factor, antibodies and muramyl dipeptides. Therefore, enhancement of KC cytotoxic functions may represent an attractive treatment modality to prevent development of liver metastases in the clinical setting.

The role of macrophages in tumor development.

Macrophages constitute a large proportion of the immune cell infiltrate, which is present in many tumors. Activation state of macrophages is greatly influenced by their environment, leading to different macrophage subsets with diverse functions. Although previously regarded as potent immune cells that are capable of destroying tumor cells, recent literature focuses on the ability of macrophages to promote tumor development due to secretion of mediators, like growth and angiogenic factors. It is now becoming increasingly clear that a complicated synergistic relationship exists between macrophages and malignant cells whereby tumor cells can affect macrophage phenotype, and vice versa. As such, macrophages and their contribution in cancer development are currently subject of debate.

Perioperative selective decontamination of the digestive tract and standard antibiotic prophylaxis versus standard antibiotic prophylaxis alone in elective colorectal cancer patients.

INTRODUCTION: Infectious complications and especially anastomotic leakage (AL) severely impede the recuperation of patients following colorectal cancer (CRC) surgery. When the normal gut barrier fails, as in AL, pathogenic microorganisms can enter the circulation and may cause severe sepsis which is associated with substantial mortality. Moreover, AL has a negative impact on the CRC prognosis. Selective decontamination of the digestive tract (SDD) employs oral nonabsorbable antibiotics to eradicate pathogenic microorganisms before elective tumour resection. METHODS: In this multicentre randomised clinical trial, perioperative SDD in addition to standard antibiotic prophylaxis is compared with standard antibiotic prophylaxis alone in patients with CRC who undergo elective surgical resection with a curative intent. The SDD regimen consists of colistin, tobramycin and amphotericin B. The primary objectives of this randomised clinical trial are to evaluate if perioperative SDD reduces the incidence of clinical AL and its septic consequences as well as other infectious complications. A main secondary objective is improvement of the cancer-free survival. A total of 762 patients will be included in total for sufficient power. CONCLUSION: It is hypothesised that SDD will reduce clinical AL thereby reducing the morbidity and the mortality in CRC patients. FUNDING: The trial is investigator-initiated, investigator-driven and supported by the Dutch Digestive Foundation (WO 11-06) and the private Posthumus Meyes Fund. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov: NCT01740947.

Macrophages mediate colon carcinoma cell adhesion in the rat liver after exposure to lipopolysaccharide.

The surgical resection of primary colorectal cancer is associated with an enhanced risk of liver metastases. Moreover, bacterial translocation or anastomic leakage during resection has been shown to correlate with a poor long-term surgical outcome, suggesting that bacterial products may contribute to the formation of metastases. Driven by these premises, we investigated the role of the bacterial product lipopolysaccharide (LPS) in the generation of liver metastases. Intraperitoneal injection of LPS led to enhanced tumor-cell adhesion to the rat liver as early as 1.5 h post-administration. Furthermore, a rapid loss of the expression of the tight junction protein zonula occludens-1 (ZO-1) was observed, suggesting that LPS disrupts the integrity of the microvasculature. LPS addition to endothelial-macrophage co-cultures damaged endothelial monolayers and caused the formation of intercellular gaps, which was accompanied by increased tumor-cell adhesion. These results suggest that macrophages are involved in the endothelial damage resulting from exposure to LPS. Interestingly, the expression levels of of ZO-1 were not affected by LPS treatment in rats in which liver macrophages had been depleted as well as in rats that had been treated with a reactive oxygen species (ROS) scavenger. In both settings, decreased tumor-cell adhesion was observed. Taken together, our findings indicate that LPS induces ROS release by macrophages, resulting in the damage of the vascular lining of the liver and hence allowing increased tumor-cell adherence. Thus, peri-operative treatments that prevent the activation of macrophages and-as a consequence-limit endothelial damage and tumor-cell adhesion may significantly improve the long-term outcome of cancer patients undergoing surgical tumor resection.

Anti-beta1 integrin antibody reduces surgery-induced adhesion of colon carcinoma cells to traumatized peritoneal surfaces.

OBJECTIVE: To study the mechanisms behind surgery-induced augmentation of tumor outgrowth. SUMMARY BACKGROUND DATA: Surgery provides the best chance of cure for most primary intra-abdominal carcinomas. Effective treatment is however relatively frequent complicated by peritoneal recurrences, which often originate from free-floating intraperitoneal tumor cells that implant on peritoneal surfaces. We previously reported that surgical trauma promotes development of peritoneal metastases. METHODS: Evaluation of adhesion of CC531s rat colon carcinoma cell line intraperitoneally after laparotomy using in vivo, ex vivo, and in vitro models. Also, human ex vivo models were used to study peritoneal tumor cell adhesion. RESULTS: Peritoneal imprints of operated rats showed that direct damaging of the peritoneum resulted in enhanced adhesion of rat CC531 colon carcinoma cells to submesothelial extracellular matrix (ECM) proteins in vivo, which was confirmed by electron microscopy. Additionally, the inflammatory reaction of the peritoneal cavity led to retraction of mesothelial cells, hereby also exposing ECM at peritoneal surfaces that had not been traumatized directly. Furthermore, we demonstrated that beta1 integrin subunits represented the primary mediators involved in adherence to either isolated ECM components or excised traumatized rat and human peritoneum. Importantly, incubation of CC531s cells with anti-beta1 integrin antibodies resulted in a significant decrease of tumor cell adhesion in vivo. CONCLUSIONS: Surgical trauma results in exposure of ECM at directly and nondirectly damaged peritoneal surfaces, leading to increased beta1 integrin-dependent tumor cell adhesion. Perioperative therapies, which aim to block beta1 integrin subunits, might therefore serve as new clinical tools for the prevention of peritoneal recurrences.

Tumor infiltrating macrophages reduce development of peritoneal colorectal carcinoma metastases.

Macrophages generally constitute a major component of tumor stroma, and possess either tumor growth promoting or inhibiting capabilities. Classically activated macrophages exert cytotoxicity and produce inflammatory cytokines, which limits tumor growth. By contrast, alternatively activated or M2 macrophages induce tumor progression by stimulating angiogenesis and proliferation. Previously we showed that resident macrophages control metastatic spread of coloncarcinoma cells in liver and peritoneal tumor models. However, it is proposed that newly recruited macrophages develop into tumor-associated M2 macrophages, as they are exposed to a microenvironment that favors alternative activation. Previously we showed that monocyte migration was diminished after flavonoid treatment in an experimental autoimmune encephalomyelitis animal model. In the present study, we investigated the role of newly recruited macrophages in colon carcinoma development, by using the flavonoids rutin and luteolin to reduce monocyte migration into peritoneal tumors. Increased tumor development was observed in animals that were treated with rutin and luteolin. Immunohistochemical analyses showed that the number of ED2(+) resident macrophages was normal in tumors of animals that received rutin and luteolin treatment. However, the number of ED1(+) cells (marker immature macrophages) was reduced, indicating decreased macrophage recruitment. Thus, inhibition of monocyte migration promotes tumor growth, supporting that not only resident, but also newly recruited macrophages limit peritoneal colon carcinoma metastases development.

Macrophages direct tumour histology and clinical outcome in a colon cancer model.

Macrophages generally constitute a major component of the tumour stroma. Although conventionally considered to be cytotoxic effector cells, macrophages have recently been described as promoters of tumour progression. The present study shows that selective depletion of peritoneal or liver macrophages prior to CC531 tumour cell inoculation resulted in highly differentiated tumours in rats. In contrast, tumours from control rats, in which macrophages are abundantly present, showed a desmoplastic stromal reaction with hallmark features of malignancy, such as neovascularization and matrix remodelling, indicating that the presence of macrophages is associated with malignant histopathological differentiation. Remarkably, macrophage-depleted rats, bearing highly differentiated tumours, had a worse prognosis, as they displayed a higher tumour load and poorer survival. Thus, while macrophages direct tumours towards malignant tumour histology, their role in anti-tumour defence is important. The selective inhibition of macrophage functions involved in malignant progression without interfering with cytotoxic ability may therefore identify important new targets for cancer therapy.

Prolonged maturation and enhanced transduction of dendritic cells migrated from human skin explants after in situ delivery of CD40-targeted adenoviral vectors.

Therapeutic tumor vaccination with viral vectors or naked DNA, carrying the genetic code for tumor-associated Ags, critically depends on the in vivo transduction of dendritic cells (DC). Transfection of predominantly nonprofessional APC and only small numbers of DC may hamper proper T cell activation. Aim of this study was, therefore, the targeted, selective, and enhanced in situ transduction of DC. A human skin explant model was used to explore targeted transduction of cutaneous DC after intradermal injection of a bispecific Ab conjugate to link adenoviral (Ad) vectors directly to CD40 on the DC surface. A significantly enhanced transduction efficiency and selectivity, and an increased activation state of migrating DC were thus achieved. Moreover, DC transduced by CD40-targeted Ad maintained their Ag-specific CTL-stimulatory ability for up to 1 wk after the start of migration, in contrast to DC transduced by untargeted Ad, which had lost this capacity by that time. Because DC targeting in vivo might obviate the need for the in vitro culture of autologous DC for adoptive transfer, CD40-targeted Ad vectors constitute a promising new vaccine modality for tumor immunotherapy.